1. Field of the Invention
The present invention relates to an automatic exposure control function in an imaging apparatus such as a digital camera or a digital video camera.
2. Description of the Related Art
In an imaging apparatus such as a digital camera or a digital video camera, control is performed by adjusting a diaphragm value, a shutter speed, an imaging sensitivity or the like to automatically set proper exposure. As long as there is no special instruction such as AE locking for intentionally fixing an exposure value, automatic exposure control is operated to always set exposure to a proper value.
For example, in Japanese Patent Application Laid-Open No. 2000-41178, to properly perform automatic exposure control, any one of average light metering, center-weighted light metering, spot light metering, multipattern light metering (split light metering or evaluative light metering) and the like is selected.
Automatic exposure control is generally performed based on luminance obtained from image information at the time of photographing. When an object having luminance greatly different from current luminance, that is, an object of extremely high or low luminance, passes through an imaging area during photographing, the automatic exposure control is temporarily affected by the object which entered the area. In other words, an exposure control state is changed while the object of different luminance passes through the photographing area. After the object of the different luminance level passes through the photographing area, the original exposure control state is restored. However, a photographed image is poor to see.
For example, in the case of performing light metering by weighting each divided area to make proper exposure of an area in which a main object is assumed to be present, when a target of extremely high or low luminance passes through an area of a large weight in a photographing screen, it temporarily causes an extreme change in exposure value.
Entry of an object in an image which a photographer does not desire, or crossing of a human or a car between an object and a camera often occurs during photographing. If automatic exposure control is accordingly triggered, exposure may be improperly controlled. Thus, there is still room for improvement.